The present invention relates to an automotive control apparatus and method, or more in particular an apparatus and a method for controlling the output of a power train including an engine, a transmission and driving wheels in accordance with the intention of the driver and the result of recognition of other vehicle running immediately ahead.
A conventional technique for changing the drive mode of an automotive vehicle in accordance with the conditions of other vehicle running immediately ahead or the intention of the driver of vehicle is described in Japanese Patent Application Laid-open No. JP-A-47862. This patent publication discloses a method of switching the drive mode of a vehicle in accordance with the driving condition of other vehicle running immediately ahead or in accordance with the intention of the driver of the concerned vehicle, as selectively judged by the driver of the following vehicle. In other words, the driver of the own vehicle determines one of the two drive modes by his or her own judgment so that the driver can drive his or her vehicle with the driving force as intended.
Establishment of a technique for detecting the distance between and relative speeds of one vehicle and another vehicle running immediately ahead (including an obstacle lying ahead) by use of a radar for securing the safety of the following vehicle is an urgent current problem. In the prior art described above, it is indispensable to attain the drive mode intended by the driver (the linear feeling of acceleration corresponding to the accelerator pedal stroke) and to secure the safety (collision prevention) at the same time.
In the conventional method of controlling the drive mode of a vehicle which still finds applications, however, primary emphasis is always placed on the intention of the driver. Therefore, it is technically difficult to automatically switch the drive mode of a following vehicle taking both the safety of the particular following vehicle and the driving condition of a vehicle running immediately ahead into consideration. This switching operation has hitherto been left to the manipulation of the driver of the following vehicle. As a result, if the difference is large between the calculated control parameter values of the above-mentioned two drive modes, the torque changes so abruptly that an unexpected acceleration/deceleration change occurs unavoidably against the will of the driver of his own vehicle.
In the prior art, assume, for example, that the driver who has so far maintained the accelerator pedal stroke at a low value switches to a mode corresponding to the driving condition of a vehicle running immediately ahead, i.e. a mode for chasing the vehicle running immediately ahead. A deviation occurs between a target value intended for by the driver of the vehicle and an actual target control value for the chasing operation, thereby causing an undesirable torque change uncomfortable to the driver of the vehicle.
JP-A-7-189795 and JP-A-8-304548 disclose that an engine and a transmission are controlled with the control parameter such as a driving torque at a output shaft of the transmission.